Rotational isomerism and defect-induced resonance modes in the skeletal vibrational spectrum or perdeuterated polyethylene

Based on the Green function method adapted to polymers and using three different force fields for the polyethylene skeleton, extensive calculations were made on the characteristic vibrational features of conformational defects in deuteropolyethylene for the frequency range 40-456 cm-1. The results presented show that almost no specific conformational information can be obtained from the defect-induced modes below the torsional cut-off nu 9(max); however, resonances above nu 9(max) may be used to advantage for spectroscopic investigations of the morphology of polyethylene.